it should be somehting like this fedora-release-12-2.noarch.rpm or this one fedora-release-12-1.noarch.rpm the fact your using Ubuntu's Grub shouldnt effect the problem you have. you might wanna grep those rpm's. also do a check to see if you have this rpm fedora-release-notes-12.0.0-4.fc12.noarch.rpm

I think what yum is doing is tagging any package that came out of an *-updates-testing repo as @rawhide.
I saw this on all the kmod-nvidia packages after I installed from the rpmfusion-nonfree-updates-testing repo. That was just before they pushed all those kmods into the regular *-updates repo. Now ,after a couple of kernel and kmod-nivida updates, they are all tagged normally, as coming from rpmfusion-nonfree-updates repo.